Fuente TeX:

\begin{array}{l}\Phi (\varphi ,\theta ) = \left( {\frac{{\cos \varphi \sin \theta }}{{\sqrt {1 + 2{{\cos }^2}\theta } }},\frac{{\sin \varphi \sin \theta }}{{\sqrt {1 + 2{{\cos }^2}\theta } }},\frac{{\cos \theta }}{{\sqrt {1 + 2{{\cos }^2}\theta } }}} \right)\\\theta  \in \left[ {0,\frac{\pi }{2}} \right]\\\varphi  \in \left[ {0,2\pi } \right]\end{array}